The present invention is a novel object ball for use in the game of pocket billiard and a method of using the training ball and a method of instructing a person how to sight and aim a cue ball through the aid of the novel pocket billiard training ball which serves as the object ball.
In the game of pocket billards, an object ball 10 is struck by a cue ball 12 which is propelled toward the object ball by the force of a cue stick 14. The purpose of the game is to sink the object ball 10 into a pocket, such as pocket 16, without sinking the cue ball 12 in any pocket on the billiard table.
It is well known that an object ball travels along a straight line originating at the point where the cue ball contacts the object ball and extending through the center of the object ball. In view of this fact, players of pocket billiards picture an imaginary line (represented in FIG. 1 by arrow 18) from the center of the pocket through the center of the object ball. The termination point 20 of imaginary line 18 is the point that the cue ball should contact in order to make pocket 16. For example, if cue ball 12 contacts object ball 10 at point 20 along imaginary line 18, object ball 10 will travel toward pocket 16 along that imaginary line 18. It makes no difference where the ball 12 is located on the table, so long as the cue ball can make good contact at point 20. If good contact is made by the cue ball at point 20 on the object ball, object ball 10 will travel along line 18.
Unfortunately, aiming the cue ball 12 so that it strikes the termination of the imaginary line that bisects the object ball and the pocket to be made is difficult because the shooter cannot easily see the point of contact when he is positioned low behind the cue ball. It should be apparent that the cue ball blocks out or eclipses the point of contact desired when the head of the shooter is low and behind the cue ball.
As a result, billiard players have developed various methods of sighting the correct contact point on the object ball. One common method of sighting is the method known as sighting by object ball displacement. This method of sighting is shown schematically in FIG. 2. Basically, a player aims at the point of contact by lining up one edge of the cue ball with the corresponding edge of the hidden area of the object ball that is obstructed from the shooter by the cue ball.
FIG. 2 shows four shots that can be made by using this method of sighting by object ball displacement. One shot is the shot known as a "full-ball" shot and is shown schematically in FIG. 2 by cue ball 22 striking object ball 24 and sending it on into pocket 26. Each of the other three shots are described in reference to sinking an object ball into pocket 26. In FIG. 2 the hidden area of the object ball that is eclipsed from the shooter by the cue ball is cross-hatched or shaded.
In order to make a full-ball shot, the shooter lines up the edge of the cue ball 22 with the edge of object ball 24 as is shown by sight line 28. To make a "three-quarter ball" shot, the shooter lines up the edge of cue ball 30 so that one edge will be in line with the edge 32 of the hidden area 34 of object ball 36. This is shown schematically by sight line 38. By aiming the cue ball in this manner, the cue ball will strike object ball 36 at contact point 40 which is the end of an imaginary line bisecting the object ball and pocket 26.
A "half-ball" shot is made in a similar manner. Here the shooter lines up an edge of cue ball 42 so that an edge is in line with the corresponding edge of the hidden area of the object ball 44, as is shown by sight line 46. To make a "one-quarter ball" shot, the shooter sights along sight line 48 so that the edge of cue ball 50 is in line with the edge of the one-quarter area of the object ball 52 which is obstructed from the shooter's vision by the cue ball 50. A "thin ball" shot is also made in a similar manner by sighting along sight line 54 so that the edge of cue ball 56 is in line with the edge of the thin hidden area. At this point, it should be noted that the terms thin ball, etc. describe the portion of the object ball that is hidden or obstructed from the shooter's vision by the cue ball. Thus, with a full ball shot, the complete object ball is eclipsed by the cue ball; whereas, in a three-quarter ball shot, three quarters of the object ball is obstructed or eclipsed by the cue ball.
The foregoing method of sighting the cue ball is difficult for the beginner to master and understand because he has difficulty in determining the exact position of the edge of the hidden area of the object ball.